Curved closure device



NQv. 20, 1956 P. GRAHAM 2,770,850

I CURVED CLOSURE DEVICE Filed Jan. 8, 1952 FIGQI FIG? |50 IO 5C FIG. I3 A7 W772i?.

I3# f THT?" i lOb INVNTOIL PHILLIP GRAHAM United States Patent() CURVED CLOSURE DEVICE Phillip Graham, Pittsburgh, Pa.

Application January 8, 1952, Serial No. 265,465

14 Claims. (Cl. 20-35) This invention relates to a closure device such as a door, shutter, folding partition section, or a barricade section, which is curved, light in weight, strong and which can have a cushion-seal to make a tight closure. It 1s .of such construction as to maintain a true bearing edge with the door opening and thus not warp as do many common flat doors.

An object of my invention is to provide a low cost, strong, durable, attractive door or the like, able to resist destructive forces resulting from catastrophes including that from hurricanes and explosions and which will resist deterioration from exposure to the elements.

Other objects of my invention are to provide substantially improved doors or the like and methods which will become more apparent from the following description taken with the accompanying drawings wherein:

Figure 1 is an elevational view of `a curved door.

Figure 2 is an enlarged fragmentary sectional view taken along line `2-2 of Fig. 1.

Figure 3 is an enlarged sectional view through a resilient seal-cushion shown in Fig. 2.

FigureA 4 is an enlarged fragmentary sectional view taken along line 4-4 of Fig. 1.

Figure 4A is an enlarged fragmentary sectional view similar to Fig. 4 but showing a modification.

Figure 5 is an enlarged fragmentary sectional view taken along line 5--5 of Fig. l.

Figure 6 is a schematic diagram, showing the control of distortion along the width of the door shell.

Figure 7 is ,an enlarged fragmentary sectional elevational view taken along line 7-7 of Fig. l.

Figure 8 is an enlarged fragmentary sectional view taken along line 8 8 of Fig. 1.

Figure 8A is a view similar to Fig. 8 but showing a modification.

i Figure 9 isv anA enlarged fragmentary sectional view taken along'line 9-9 of Fig. 1.

Figure 9A is a view similar to Fig. 9 but showing a modification. V l

Figure 10 is a fragmentary sectional view through a modified curved door. n

Figure 11 is an elevational view of a modification taken along the side edge of a door curved longitudinally and laterally.

Figure 12 is a fragmentary sectional plan view taken through a further modified door.

Figure 13 is ya sectional elevational view taken along line 13-13 of Fig.l2.

Figure 14 is a fragmentary sectional view through a marginal portion showing a door seal-'cushion for a modified door.

In general, the door or shutter shown in Fig. l is lightweight, strong, and durable. It is low in cost to build, install and maintain. The curved door is strikingly different from conventional building doors, and it is attractive` in appearance. The curved effect gives the impression of strength and beauty.,

Patented Nov. 20, 1956 ICS Thisk curved door would require less material than would common flat doors of equal strength.

The door shown in Fig. l is illustrated as an exterior door with the arched shell bowed to the exterior to resist high exterior pressures. This would be an exceptionally sturdy door arrangement, capable of resisting pressures from abnormal conditions, such as exterior explosions in wartime or peace, high winds from hurricanes, force of tidal and fresh water floods, force of avalanches, forcible entry of undesirable persons or ani- Vmals, and impacts from missies carried by the force of explosions and winds. A continuous, resilient, sealed cushion around the edge of the door insulates to prevent the passage of insects, rodents, dirt, fumes or odors, moisture, sound, light, heat, cold, smoke, tidal or fresh flood waters, and, since it would retard the progress of fire, is a fire seal. It seals in air for .air-conditioning. In wartime, this seal on the door would prevent the passage of poisonous gas, smoke, bacteria, and radioactive dust o'r mist from an atomic blast. A door equipped with an edge cushioned-seal closes noiselessly. The seal-cushion would also take up the slack caused by discrepancies in the door or door opening. Thus, a less accurate door opening is required, therefore, a costly door frame is unnecessary. There would evolve no future door trouble caused by slight settling of the building and untrued openings due to the settling.

l Curved -door shell 1 is bowed in width to create an arch. This shape is strong, to resist pressure on the outside of the arched surface and to allow for expansion and contraction in the shell without objectionable cracking or warping. The curved shape of the door shell offers considerable resistance which would restrain excessive warping of the boards or other shell members. The curved shell 1 hasa high section modulus to prevent bending lengthwise, caused by exterior pressure or minor stresses resulting from expansion and construction due to differences in temperature or moisture in the door parts. An exterior thrust against the arched shell 1 can carry the load to the ldoor jamb or wall effectively.

Since possible loads on the arched shell effect compression in the arch, the door shell 1 may be constructed of any one of many building materials which is strong in compression. Low cost wood may be utilized for a door shell of this design, since the wood need not be the very strong, thick, or of a seasoned grade, necessary for a flat door. The door shell may be made of random' length lumber. Pieces of lumber forming shell 1 would likely be placed length-wise. Their edges may be bonded together by being tongue and grooved or glued. The door shell 1 may be made of plywood, etc., laminated in thickness, metals, plastics, or concrete, as well `as wood. Glass would also'be a suitable material for the curved door shell. Door shells of materials with good bending' l curvatures on both sides, the same as the shell 1h shown in Fig. l2, which will be described in detail later.

Referring to Fig. l, side members 2 form trim, stiften the side edges of ythe door, and are grooved to hold the resilient cushion-seal 12. Side members 2 are fastened to door .shell 1 with screws or other suitable means. Top and bottom ribs 4, and intermediate ribs 5, stiffen and help to hold `the curved shell 1 to a bowed shape. Ribs 5 may be `omitted when possible loads are light. Ribs are shaped to allow control-led outward expansion and inward contraction throughout the width of the shell l. Hinges 6 and lock 7 of any suitable type, are placed to suit the door. The intermediate rib 5 is shown in Figures 2, 4, and 8. Figures 5, 7, and 9 show ribs 4 which are is shown in Fig. 7.

similar to ribs 5, with rib flanges 4a. Ribs 5 are connected to the shell 1 by screws 8. Rib flange 5a is connected to rib 5 by screws 9. Flange 5a stiffens rib 5, covers adjustable wire tie and acts as a trirn. Wire 10tcan take the thrust. restraining the arched door width from spreading and fiatteniug. These ties 10 are covered `to protect them from corrosion and for appearance. One or both ends of wire 10 are threaded. As shown in Fig. 4, a slotted nut 10a is turned for adjusting che effective length of wire 10, to maintain the desired door width. Counterbored recessed holes in side members 2 retain nuts 10a. The edge of rib 5 contacts shell 1 only at spaced points near screws 8. Between screws 8, ribs 4 and 5 are cut back from the contour of shell 1 to allow gaps 4b and 5b, which allow contraction `of the shell 1. These gaps may be left open between shell 1 and the ribs; or, if desired, a resilient filler 11, such as one made of resilient rubber, felt, or plastic, may be used as a gap filler. To hold filler 11, the cuts on the ribs are grooved slightly. The ribs 4 and S, especially the bottom rib, would probably have the resilient filler 11 inserted in the gaps to prevent dust and dirt accumulation and to insure a neat appearance. lf an exterior door of this type is made Without the seal 12, the filler 11 would likely be useful on the top and bottom ribs, and they may be of water-resistant material, such as rubber, in order to exclude moisture and air.

Where the ends of the door ribs 4 and 5 are adjacent to side members 2, adjustment is made to maintain the correct door width by trimm-ing down the rib ends or wedging the `ribs from side members 2. Wire 10 is used as a take-up in adjusting. When the side edges of shell 1 are not to take the thrust of the load against the door jambs, the ties 10 take the thrust from the shell. Sealcushion 12 is fitted into a dovetailcd groove around the door perimeter. It acts as a seal, a cushion, and a trim. It hides the holes for the ends of wires 10. On a modified door (not shown) without a seal, the dovetailed groove is omitted. The holes for wire 10 should be plugged up when the seal is not incorporated in the door. Seal 12 cushions the door, allowing it to close silently. Pressure on the outside of shell 1 has a tendency to compress seal 12, thus creating a larger bearing surface with the building wall. With higher pressure on `the door shell, the seal becomes flatter and tighter. Thus the thrust from the door shell 1 is evenly distributed to the door jambs or wall. The resilientI seal overcomes small discrepancies in the door `opening and the door which would otherwise prevent a good bearing surface. Since seal 12 would allow more tolerancein hanging the door than is possible with ordinary flat doors, the present door could be easily and quickly erected. On light wall construction, doors may be hinged yto the floor and ceiling, with no heavy loads being. transferred to the walls or jambs.

The door jamb, formed by wall 13, is indicated by a dot-dash outline. Door jambs are shown beveled to receive the seal 12, and thus the thrust of door. The door jarnb has an offset to prevent visibility from either side through any slight crack along the door sides. The threshold is shown in Fig. 9; seal 12 bears against ,it. The lintel above the door, formed by the building wall, It is projected out from the Wall to divert the rain from the door opening. The hinges 6, shown in Figs. l `and 5y may have resilient spring steel straps `to allow them to bend when high pressures are eX- erted on the convex surface of the door. Thus the load may be transmitted through the door edges to the openlng, rather than to the hinges 6. Hinges 6 may be grouted to a masonry wall after the door hasbeen set accurately. The seal 12 compresses slightly when the dooriis closed. The latch on lock 7 engages a suitable slotted catch on the door jamb to allow the door to move in when outside pressure is increased.

Locks are preferably attached to the exposed inter-i01- side of the door at little cost, rather than being recessed into the edge. The swing of the door may be reversed in modifications (not shown); especially where weather resistance is not required. Either side of door may be modified .to fit conventional door frames, with or Without a door seal.

Figure 6 is a schematic diagram showing the distortion of the door shell 1 along its width, which results from expansion and contraction. The solid curved line 1a indicates the normal contour of the door shell. The fixed points 8a are located by the use of screws 8. Screws 8 tie the door shell 1 and ribs together. Also they divide the shell bending area into three small incremental areas or zones. There may be more or fewer bending zones than the three shown in modifications (not shown). Bending zones allow unobjectionable bending in the arched shell 1, without causing undesirable warping of the door. The door shell 1 bends locally in width and the strong curved shape restrains it from bending lengthwise. The door shell is restrained from spreading by the ribs, wire ties, and door jambs. The bending in the curved door would be so slight that no objectionable cracks would be made in the shell. When the door shell 1 expands due to increased moisture or increased temperature, it takes on the bulging contour in the bending Zones between points 8a, shown by dashed line 1b. The cooling of all doors, and drying out in wooden doors, causes contraction, which, without localization, causes warping and cracking. The curved shell 1 allows the curved width to flatten out locally in the bending zones for contraction. When the door shell 1 shrinks, it takes the contour indicated by dot-dash line 1c in Fig. 6, which flattens between points 8a.

A modified door shell similar to that shown in Fig. l2, may be used with the door shown in Fig. l. This door shell has identical curvature on each side which makes it thicker towards the center similar -to a crescent. The shape is strong and it may be used with or without the intermediate connections to ribs. It would in general,

bend without objectionable distortion, from uneven pres-` sure on it.

The interior or fiat side of the door shown in Fig. l may have a light-weight panel covering such as a wooden panel or mirror 20 fastened on it. Various types of insulation may be placed between the curved shell and the panel 20. Sand and water may be inserted into the door as an insulation or barrier against the heat and harmful gamma rays emitted by atomic explosions. The panel 20 may be hinged to form a closet space in the door. Ribs in the door may act as shelves, when slats 21 (only one being shown) are placedA above the ribs to keep articles from falling off. This arrangement would be practical for closet doors, bedroom doors, and bathroom doors. Shoes and other items could be stored in the shelves and still be accessible. A window 22 with a resilient frame may be placed in the shell. A resilient Window frame would allow for bending in the shell and still maintain a seal.

A mail slot 23 with a resilient seal may be placed in the shell. A cross slat 21 below the mail slot, would help form a rack to catch the mail.

A bathroom door may have towel hangers 24 (only one being shown) attached below the ribs.

Figures 4A, 8A, and 9A show modifications for a door `or shutter made of such materials as concrete, plastics,

or glass. Reinforcing is imbeddedin the door members for strength. The reinforcing material may be metal or any other material that will offer strength. Renforcing such as fiber glass is especially suitable for plastics. The door may have a laminated shell made of various types of materials. The door may be suitably constructed with strong, durable water repellent, insulated, light-weight, reinforced concrete or plastic. A large ratio of vermiculitev in such a concrete` door would make it light-weight, tire-resistant, and an insulator for sound` and heat. Teraffrontov mites, vandals, and some other destructive` elements could not destroy these durable concrete doors. A resilient seal 12'around the door perimeter would act as a seal and a cushion to prevent breakage. These reinforced doors may be made with substantially the same design used for wood construction. A concrete door would thus be somewhat modified as compared to wood construction, since concrete, plastic, and glass can be cast into various shapes. In this construction, reinforcing is used to take the tension and shear and thus to prevent cracking caused by loads, temperature and moisture changes.

Wire fabric reinforcing 14, shown in the curved door shell 1d, may be very light wire with small mesh to keep the concrete or plastic lcracks small. Since concrete and plastics are poor in tension, they have a tendency to crack. Reinforcing bonds with concrete or plastic to maintain uniform expansion and contraction. Three vertical reinforcing wires a are tied together and imbedded in side members 2a, which are similar to sides 2. Reinforcing wire 15 is embedded in rib 5c which is similar to rib 5. For this construction, tie wire 10 should have reinforcing 15, either welded to it or fastened by other means, such as by twisting together. Curved, reinforced shell 1d is similar to shell 1. Bottom and top ribs 4c are as shown in Fig. 9A. The countersunk machine screws 16 may fit into the holes in the sleeves 16b, which are cast within shell 1d and welded or otherwise fastened to wire 14. Screws 16 engage nuts 16a, which are embedded in the ribs. Nuts 16a are welded to reinforcing l5. Thus the ribs and shell 1d may be made'separately and then joined together. Ribs 4c and 5c differ from ribs 4 and 5 in that the flange is cast as part of the main rib piece. Modifications may be made, such as casting the door in one piece, or casting the shell and side pieces into one piece. A door may have its members made of different types of materials, such as a door with a glass shell and plastic ribs, etc.

Figure 10 is a fragmentary sectional plan view taken through an intermediate rib of a modified door. This door has two curved shells. It is similar in design to two single curved shelled doors placed back to back. This door may be made economically of reinforced concrete, plastic, wood, glass, or metal. Ribs 17, although shown as one piece, may also be made in two pieces. Ribs 17 may be grooved to receive the tie Wire 10. In the case of a door with cast parts, Wire may be cast into the ribs. Side members 18 may be made either in one or two pieces. The second curved shell 1e would have a different edging to suit seal 12.

This door may be used where possible pressure is great from either side of the door, or for appearance to keep the same type of surface on both sides of the door. The space between the shells may be filled with insulation (not shown).

Figure ll is an elevation of another modification of a strong door or shutter that may be used in arch construction. The dished shell 1g is similar to the curved shell 1, except that it would be curved in length to suit the curvature of the arch in building shell 19, in addition to the curve in the width of the door. The ribs and other members would be similar to the doors shown in Figs. 1 to 9A inclusive. This two-way curving of the door would allow outward and inward bending caused by expansion and contraction, thus reducing undesirable distortion and cracking in both directions.

Figure l2 shows a modification of the door or shutter similar to that shown in Fig. 1 and it has a curved shell 1h, without any ribs or side members. Figure 13 is a sectional elevation and Fig. 14 is a fragmentary sectional view of an edge. This curved shell 1h has identical curvatures on both surfaces, which causes the door to thicken towards the center, similar in shape to a crescent. This shape makes a stronger shell which would be able to resist pressures without objectionable bending. A modilied shell similar to shells 1 or 1d may be used in place of shell 1h. Shell may be a flat panel bowed and held by tie wire 10b, or strut 25. The shellmay be reinforced (not shown) the same as is shell 1d. A modied resilient seal-cushion 12b would act similar to seal 12. A modified tie wire 10b would act similar to wire 10. A strut 25 may be used to prevent the shell chord width fromy expanding or contracting. Strut 25 may be omitted when conditions are such that the chord width of the shell would not have a tendency to change. Also wire 10b may be omitted when the door cannot spread. When strut 25.

is used, the tie wire 10b may be omitted as the strut can take tension and compression. The threshold and lintel are curved to match the curvature of the door. The edge of shell 1h may have beadings along each side of the edge as shown in Fig. 14, to retain seal 12b.

A series of doors such as that shown in Fig. l2, with suitable hinges, may be used to make a folding door, partition, or barricade. Faces of adjoining doors may be positioned to make a serpentine or corrugated arrangement. As barricades they may be fastened down to a floor and to a support above, or may be braced into position. Without wires 10b and tubes 25, the door sections would nest together when folded. Curved doors and shutters, similar to the doors shown and described, are useful in resisting damage by hurricane winds or water entering buildings. Shutters may be removable with the hinges, etc., left on the building. Such shutters as those made with shell 1h and seal 12a would nest together in a small storage space. Curved rolling doors and overhead doors would be simple modifications (not shown). Other door` and shutter modifications would be possible employing this type of construction.

Thus it will be seen that I have provided an efficient and amazingly strong closure element, in the form of a door, shutter or the like, which provides optimum strength for a given weight, and which by curvature of one or both panels, makes it possible to withstand abnormal wind forces; also, I have provided novel ribs for such closure element which have spaced anchoring points across the width of the closure element Iand between which anchoring points a small space is provided between the curved panel (or panels) of the door and ribs soy as to permit free outward or inward bowing of the panel portions, such as caused by temperature or humidity changes, thereby providing uniform distribution across the width of the closure element of such bowing; additionally, I Ihave provided a closure element which may be made of wood, reinforced plastic or concrete or other suitable materials and which may be provided with a resilient sealing material about its perimeter and the interior of which may be filled with insulating material.

While I have illustrated and described several specific embodiments of my invention, it will be understood that these are by way of illustration only, and that various changes and modifications may be made within lthe contemplation of my invention and within the scope of the following claims.

I claim:

l. A closure device comprising Ian outwardly curved thin panel, a plurality of elements whose extremities are fastened adjacent the extremities of said panel on opposite sides thereof, and a plurality of ribs, each having spaced anchoring points secured to one side of said panel there being spaces between said ribs and said one side of the panel, between said anchoring points, for allowing said panel to freely expand or contract at intermediate unfastened portions between said anchoring points.

2. A closure element comprising an outwardly curved panel, a plurality of transversely extending ribs secured to said panel in spaced parallel relationship, each of said ribs having spaced projecting portions which are anchored to transversely spaced portions of said panel, there being a space between the intermediate unfastened edge portions of said ribs and the panel, between said anchored projecting portions so as to allow contraction of the panel as the result of reduced temperature without obstruction from said intermediate edge portions.

3. A door comprising a thin, outwardly bowed panel of substantially rectangular shape and bowed across the width of the door, a plurality of ribs secured to'said panel in spaced parallel relationship, each rib extending across the width of the door, each of said ribs being of polygonal shape having spaced projecting corners which are anchored to said outwardly bowed door panel and between which, spaces are provided for allowing free outward or inward movement of unfastened door panel portions which extend between said anchoring projections.

4. A door comprising anoutwardly bowed panel, a plurality of spaced parallel ribs, each extending along the width of the door, and each provided with a plurality of angularly disposed edges facing in spaced relationship but not attached to said panel and providing corners which are anchored to spaced portions of the panel along the width of the door, and a at panel spanning the concaved face of said panel and secured to one of the edges of said ribs, whereby the outwardly bowed panel may freely expand or contract between said anchored corners as the result of temperature changes.

5. A closure element comprising an outwardly curved thin panel, a plurality of transversely extending, spaced parallel ribs, each having projecting portions which are secured to transversely spaced portions of the panel and intermediate portions which are spaced and unsecured to said panel, and a strip of resilient material surrounding the perimeter of said outwardly curved panel.

6. A closure element as recited in claim wherein a cavity is provided within said resilient material and which extends throughout the entire perimeter.

7. A closure element as recited in claim 2 wherein the space between said edge portions of said ribs and said outwardly curved panel is filled with yieldable material.

8. A closure element as recited in claim 4 wherein yieldable heat insulating material is provided in the space between said at panel and said outwardly bowed panel.

9. A closure element as recited in claim 1, together with a pair of hinges of yieldable material for hinging said closure element to an opening in `a building wall so as to allow an edge of the closure element to bear against an edge of said opening.

10. A closure element comprising an outwardly bowed 5i panel of. uniform curvature in the same direction, a plurality of tie elements disposed in spaced parallel relationship for maintaining said outward bow of said panel and including tie elements at the extremities of said panel, each of said tie elements having its extremities secured to` opposite portions of the width of the panel, a thin ilat panel secured to said tie elements, and a lling of heat insulating material between said at panel and said outwardly bowed panel.

11. A door as recited'in claim 3, together with a plurality of transversely extending slats disposed immediate ly above and adjacent said ribs for making said ribs useful as shelves.

12. A door comprising panels bent outwardly on its opposite surfaces along the height thereof and a plurality of polygonally shaped ribs disposed between said panels and arrangedin spaced parallel relationship, each rib extending across the width of said door and the corners of each of said ribs being anchored to said panels, portions of said ribsy intermediate said anchoring corners being spaced from and relatively movable with respect to said panels to allow free inward or outward bowing of said panels.

13. A door as recited in claim 3 wherein said panel and said ribs are of plastic material, each having reinforcing means embedded therein.

14. Adoor as recited in claim 3 wherein said panel and said ribs are of reinforced concrete.

ReferenceSCited in the tile of this patent UNITED STATES PATENTS 1,346,229A Mecham July 13, 1920 1,895,553 Nordell Jan. 31, 1933 2,121,826 Roberts June 28, 1938 2,263,806 Hammerl Nov. 25, 1941 2,328,761 Wamnes et al. Sept. 7, 1943 2,346,641 Ashbaugh Apr. 18, 1944 2,479,819 Dc Ragon Aug. 23, 1949 FOREIGN PATENTS 701,456 France Jan. 7, 1931 719,456 France Nov. 14, 1931 752,843 France July 24, 1933 549,130 Great Britain Nov. 6, 1942 63,387 Denmark Apr. 3, 1945 

